算法-符号表

 代码

package test.symbol;



public class SymbolTable<Key,Value> {
    //记录头结点
    private Node head;
    //记录符号表中元素的个数
    private int N;

    private class Node{
        //键
        private Key key;
        //值
        private Value value;
        //下一个结点
        private  Node next;

        public Node(Key key, Value value, Node next) {
            this.key = key;
            this.value = value;
            this.next = next;
        }
    }

    public  SymbolTable(){
        this.head = new Node(null,null,null);
        N = 0;

    }

    public int size(){
        return N;
    }
    //往符号表中插入键值对
    public void put(Key key,Value value){
        //符号表中已经存在了键诶key的键值对，那么只需要找到该节点，替换键值对
        Node n = this.head;
        while(n.next!=null){
            n = n.next;
            if(n.key.equals(key)){
                n.value = value;
                return;
            }
        }

        //符号表中不存在了键诶key的键值对，创建新的结点，保存要插入的键值对
        Node newNode = new Node(key,value,null);
        Node oldFirst = head.next;
        newNode.next = oldFirst;
        head.next = newNode;
        N++;

    }
    //删除符号表中键为key的值对
    public void delete(Key key){

        Node n = this.head;
        while(n.next!=null){
            if(n.next.key.equals(key)){
                n.next = n.next.next;
                N--;
                return;
            }

            //变换n
            n = n.next;
        }
    }

    //从符号表获取key对应的值
    public Value get(Key key){
        Node n = this.head;
        while(n.next!=null){
            n = n.next;
            if(n.key.equals(key)){
               return n.value;
            }
        }
        return null;
    }

}

后面还有有序符号表，懒得看了